CONCORD, N.H. — Scott Brown, a Republican who once represented Massachusetts in the U.S. Senate, announced his second bid Wednesday for the New Hampshire Senate seat being vacated by Democrat Jeanne Shaheen next year.

Brown, 65, was born at the Portsmouth Naval Shipyard and moved to Massachusetts as a toddler. After several terms in the state Legislature, he won a special election in 2010 for the U.S. Senate seat that had been held for decades by Edward Kennedy.

He lost to Democrat Elizabeth Warren in 2012. He then moved to New Hampshire, where he unsuccessfully challenged Shaheen for the Senate in 2014. Shaheen, now serving her third term in the Senate, announced in March she would not seek reelection in 2026.

Brown also served as U.S. ambassador to New Zealand and Samoa during President Donald Trump’s first administration and briefly as dean of New England Law in Boston.

He first announced he was running to WMUR-TV.

“We’ve been blessed by two great governors, Chris Sununu and Kelly Ayotte,” Brown said in a campaign announcement video of the former and current Republican leaders. “But in Washington, we haven’t been represented by the right people.”

New Hampshire has an all-Democrat congressional delegation, with four-term Congressman Chris Pappas, 44, announcing his candidacy for the Senate seat in April.

Brown said in his video that Pappas “has stood with Joe Biden as he opened the border, drove up the cost of everything, and made life just simply unaffordable.”

Pappas responded in a statement following Brown’s announcement.

He said Brown “stands with corporate special interests, supports efforts to strip away health care coverage from tens of thousands of Granite Staters, and backs President Trump’s reckless tariffs that New Hampshire small businesses are speaking out against every single day.”

Brown announced his candidacy after Sununu declined to run. The popular governor decided not to seek a fifth, two-year term last year.